Problem using concat() on postgresQL

postgresQL does not have a native concat() function so instead drupal defines its own. However since only concat(text, text) is defined by default postgres fails to run the two queries in minutes.module which used 3 and 4 arguments, one workaround I've tried is to simply define these 2 additional functions. A perhaps better options might be to change the code so it does not use this function, anyway the 2 definitions is:
CREATE OR REPLACE FUNCTION "concat"(text, text, text) RETURNS text AS '
SELECT $1 || $2 || $3;
' LANGUAGE 'sql';
and
CREATE OR REPLACE FUNCTION "concat"(text, text, text, text) RETURNS text AS '
SELECT $1 || $2 || $3 || $4;
' LANGUAGE 'sql';